Family: Restionaceae

In my early 20s, I lived in the northwest of Germany for six months, working in an enormous export plant nursery (Bruns) for three of those months. During my practicum at Bruns, I was fortunate to live in an old ReetdachhausĀ (thatched roof house) that had formerly been the residence of previous generations of the family that owned the nursery. Although it was not a cause for genuine concern, I can report that watching sheet lightning dance across the sky as one stands beneath a thatched roof was a peculiar and mildly nerve-wracking experience (considering the nature of the material that bedecked the house).

It is interesting to reflect that thatching (which we think of as an Old World tradition, from scenes such as the Cotswolds in England) was an important building material for Maori and early European settlers – such as William Colenso, who recorded the use of oioi (Apodasmia similis) as a thatching ‘reed’ by Maori.

This makes further sense when one considers that oioi is from the restiad family (Restionaceae) – a predominantly South African family from which several species are utilised for thatching in South Africa. This form of usage is reflected in the common name dekriet (which is Afrikaans for ‘covering reed’ or ‘thatching reed’); a title that is applied to several South African restiads (particularly a couple of species of Thamnochortus).

Restiads achieve their greatest diversity in South Africa’s amazing Cape floral kingdom, where around 300 species occur, whilst Australia contains around half that number of species. Many South African species (notably from Thamnochortus, Elegia, Rhodocoma and Ischyrolepis) have been successfully trialled as garden plants within New Zealand (by the Auckland Regional Botanic Gardens and Joy Plants nursery), and a number of these deserve much wider attention from gardeners and landscapers.

The genus Apodasmia consists of just 3 or 4 species (one probably new species from Australia is undescribed), with one recognised species in each of New Zealand, Australia and Chile.

Apodasmia similis

Oioi; Jointed wire rush

Over the last two decades, this adaptable character has risen from anonymity to become an extremely popular (and excellent) landscape plant. Its appeal is easy to fathom, as it forms simple swathes of upright, reed-like foliage that are particularly well suited to modern design.

However, this alluring vision needs to be accompanied by a caveat that is not understood (or sometimes ignored) by many designers and horticulturists.

As with certain species of a similar growth form, oioi’s foliage is prone to periodically falling sideways (especially the large Chatham Islands form most commonly seen in cultivation); thereby dispensing with the neat, upright character that one may have hoped for. In one example that I have seen, a major landscape design/construction company planted oioi in a 50cm wide strip garden, along the entire length of a driveway (in excess of 15 metres).

After a period of time (probably one year to 18 months), the plant did what it naturally does and sprawled flat upon the driveway. Out came the hedge trimmers (of whomever was performing maintenance before I saw this garden), and the plants were trimmed back to ugly clumps of stalks (from which upright leaves emerged anew).

This example does not mean that one should be wary of planting this beautiful and useful plant; it just illustrates the need to be realistic in one’s expectations of how the plant will grow. It should be given sufficient space to spread (at least 1.2m where planted as individuals), and one should not rely on the foliage to stay vertical at all times.

Apodasmia similis grows within damp habitats on the margins of our coastlines and lakes, such as the Manawatu dune hollow pictured above. It is an impressive component of salt marshes and estuarine areas, where it forms large, amorphous masses that wave in the wind. The foliage normally bears a smoky, greyish-green colour, although it can take on attractive russet tones within cold weather.

It generally grows to around 1m in height, but can reach 1.5m. Although it is naturally found in damp habitats, it is capable of withstanding periodically dry conditions – or even extended periods of drought where the plant has built up enough of a root system to sustain itself (as in the case of the remarkable specimen pictured above on the Ahipara Dunes). Apodasmia similis performs best in full sun; an aspect in which its foliage tends to remain as upright as possible.